Buffon returns as Juve beat Catania
Juve, who had lost their last two league games, took the lead after 35 minutes when Serbia winger Milos Krasic scored following Alessandro Del Piero's superb cross to the far post before Simone Pepe doubled the advantage after the break.
Buffon seriously hurt his back during Italy's ill-fated campaign in South Africa in June and underwent surgery, allowing Marco Storari to take his place in the Juve goal.
Storari has impressed so much that reports have suggested the Turin club could decide to cash in on injury-prone Buffon.
Del Piero returned to the starting line-up and was soon the only striker after Luca Toni limped off.
Toni joined fellow forwards Amauri, Fabio Quagliarella and Vincenzo Iaquinta on the injury list, further highlighting Juve's need for another front-man such as target Diego Forlan.
Holders Inter Milan progressed to the quarter-finals with a 3-2 win over Genoa on Wednesday while Palermo will meet Parma in the last eight after also going through.
The remaining last 16 fixtures, including AS Roma v Lazio and AC Milan v Bari, take place next week.